SU393276A1 - METHOD OF OBTAINING PYRAZOLINS - Google Patents

Description

one

This invention relates to an IK method for the preparation of pyrazolines used in organic synthesis.

A known method of producing pyrazolines by reacting tertiary acetylene chlorides with 96% gvdrazine at 140-150 ° C. The products are isolated in a known manner. Yield 43-63%.

The starting tertiary acetylenic chlorides usually contain impurities of allene halides, which are difficult to remove due to the closest temperatures of killing of substances, which significantly complicates the formation.

In order to simplify the process, it is proposed to use allen halides, mainly chlorides or bromides, or a mixture of allene and a | cetylene halogenides with hydrazine hydrate, preferably in the presence of a catalyst, such as copper or its salt, as starting materials. The process is carried out at O-150 ° C, more often at 50-80 ° C.

With catalyst utilization, the reaction proceeds under milder conditions, and the yield of the target products slightly increases.

Products are isolated in the most suitable manner.

The structure of the obtained pyrazoliums is proved by the data of elementary analysis, IR spectroscopy and counter synthesis.

Example 1. A mixture of 21.3 g (0.145 mol) of 1-bromo-3-methylbutadiene-1,2 and 15 g. (0.3 mol)

and

if iD a ZIN hydrate is heated at 65-75 ° C, the l is transferred for 7 hours, then acidified with hydrochloric acid and unreacted with 1- bro, m-4-methyl butadiene-1,2 is extracted with ether. The aqueous solution of organic compounds is salted out with potash, extracted with ether, dissolved with sulphate of magic, water is distilled off and the residue is distilled in vacuum, yielding 7.15 g (46.4%) of 5,5-dimethyl-D2-iirazoline, m.p. 60-61.5 ° C / 32 mm; 1.4598; df 0.9192.

Example 2. As in example 1, from 10.8 s (0.1 mol) of phenyl thidrazine and 7.35 g (0.05 l (o.) 1-bromo-3-methylbutadiene-1,2, 3.7 g are obtained (43.1%) L-phenyl-5,5-dimethyl-D2-pyrazolium, m.p. 97-.99 ° C / 3.5 mm; 1.5527; rff 1.0184.

Found,%: N 16.65.

CuHuN2.

Calc. But%: N 16,10.

Example 3. In a three-tube flask was placed 7.5 g (0.15 mol) of hydrazine hydrate, 0.1 g of Madi chloride and 0.1 g of bituminous copper, at room temperature and imbalance, but 7.35 g (1 0.05 mol) 1-bromo-3-methylbutadiene-1,2, an increase in temperature to 37 ° C was observed. After moving for another 8 hours at a room temperature, the mixture is extracted with ether, dissolved in Magai sulphate, distilled off the ether, the residue is distilled in a vacuum, and 3.28 g (59.9%) of 5.5-di-2-D-2-tyrazoline are obtained, t, kip . 60-62 ° C / 32 mm; l 20 1.4600. Example 4. In a round flask, 15 g (0.3 mol) of hydrazi-npiDrata, 0.2 g of copper chloride and 0.2 g of powdered Copper were added, at room temperature and stirring to: 14.7 g (0.1 g mol) mixtures of 3brOM-3-1metiLpenten 1 and 1-broM-3-methylpentadiene-1, 2 (: 3), on dishes the temperature rises to 40 ° C. The mixture was stirred for another 10 hours at room temperature, extracted with ether, the extract was dried with magnesium sulfate and dispersed in vacuo to yield 5.6 g (57.6%) of 5.5-dimethyl-L2-py1razoline, m.p. 58-59 ° C / 30 mm; n 2 ° 1.4590. The subject matter of the invention is 4. Method of preparation; pyrazolino by the interaction of unsaturated halides with hydrazine, followed by isolation of products in a known manner, characterized in that, to simplify the process, the allenic thalogenides or a mixture of allenic and acetylene halides with hydrazine hydrate are reacted. and. Method (claim 1), characterized in that the process is carried out in the presence of a catalyst, for example, copper or its salt.